<?php
class AdminModel extends Model
{
    public function getUsers(array $conditions)
    {

    }

    public function login($username, $password)
    {
        $whereClause = "username =".$this->_db->quoteLike($username)." AND password=".$this->_db->quoteLike(md5($password)); 
        return $this->_db->fetchOne("
            SELECT admin_id
            FROM admin
            WHERE ". $whereClause ."
            LIMIT 0,1
        ");
    }

}